Physiology of pregnancy
Zhao aimin
Definition of pregnancy
Pregnancy is defined as the course of
embryo and fetal growth and
development in uterine
It begain at the fertilization and end the
delivery of the fetal and it’s attachment
Definition of fertilazation
Fertilization is defined as the course
of combination of the oocyte and
sperm
It onset 12h after ovulation usually in
ampulla of the oviduct(fallopian tube)
The Development of the
fertilizated egg
? 3 days after ovulation,the morula
(early blast)is fomulated
? 4 days after ovulation,the late blast
is fomulated
? 6-7 days after ovulation,the egg
imbeds in the uterus
The stage of egg imbed
? Apposition
? Adhesion
? Penetration
The necessary conditions
of imbed
? Disapearing of the pellucid zone
? Syntrophoblast formed from the
blast
? Synchronizing development of blast
and the endometriun
? P Secretory enough
Changes of endometrium after
the egg imbed
The
endometrium
changes into
dicedua
?Basal decidua
?Capsular
decidua
?True decidua
Attachment of the fetal
? Placenta
? Fetal membranes
? Umbilical cord
? Amniotic fluid
placenta
It’s an exchange organ between
maternal and fetal
? Amniotic membrane
? chorion frondosum
? Basal decidua
chorion frondosum
13-21 days after ovulation,villi
fomulating gradually
? Grade I viili
? Grade II Iviili
? Grade III viili
Structure of placenta
? Round
? Weight:450-650g
? Diameter:16-20cm
? Thickness:1-3cm
thick in center and thin in margin
Function of placenta
One important function of placenta is
substance exchange between maternal
and fetal
The position of exchange is VSM(vasculo-
syncytial membrane)
VSM is comprised of
? Syntrophoblastocyte
? Basal membrane of Syntrophoblastocyte
? Stroma of villi
? Basal membrane of capillary
? Endothelium of capillary
The way of substance exchange
?Simple diffusion
?Facilitated diffusion
?Active transportion
?phagocytosis
The functions of placenta
? Gas exchange
? Suply of nutrition
? Depletion of fetal product of metabolisn
? Defense function
?Hormone synthesis
?Human chorionic gonadotropin(HCG)
?Human placental lactogen(HPL)
?Pregnancy specific ?-glycoprotein(PS ?1G)
?Human chorionic thyrotropin(HCT)
?Estrogen,P,Oxytocinase,heat stable alkaline
phosphatase(HSAP)
Fetal membrane
? Chorion
? Amnion
Umbilical cord
? Length:30-70cm average:50cm
? Consist of 2 artery and 1 vein
Amniotic fluid
?Source,early from serum dialysis
late fron fetal urine
Absorse,by fetal membrane,fetal
swallowing(500ml/day)
Amniotic exchange,between maternal
and fetal 400ml/h
Volume of amniotic fluid
? 8 weeks:5-10ml
? 10 weeks:30ml
? 20 weeks:400ml
? 38 weeks:1000ml
Status of amniotic fluid
? pH:7.20
? Density:1.007-1.025
? Contained,water(98-99%)
inorganic substance
organic substance(1-2%)
The function of amniotic fluid
Protect maternal and fetal
Maternal changes during pregnancy
The maternal system may produce a
series of changes in order to adapt to the
needing of fetal growth and development
influenceed by placenta hormone and
neuro-endocrine
Changes of reproductive system
Uterus
Body,become enlargement and soft
from 7× 5 × 3cm pre-pregnancy to
35× 25 × 22cm at term
Volume of uterus cavity,
become enlargement from 5ml pre-pregnancy to
5000ml.at term
Weight,be increased from from 50g pre-
pregnancy to 1000g at term
Wall,become thickness and the thickist at mid-
period from 1 cm pre-pregnancy to 2-2.5
cm at term
Blood suply:blood flow increased significantly
upto 500- 700ml/min,increased 4-6
times and most of blood flow is
transported to the placenta(80-85%)
Isthmus,be dialated and become soft from 1cm
pre-pregnancy a portion of the uterus
after 12 gestational weeks
Cervix,be soft and coloration or stain
secrete amount of mucus avoiding the
uterus cavity suffer from infection
Changes of ovary
? Stop ovulation
? Corpus luteum formation and maintains for
10 weeks
? And the function of corpus luteum is
substituted by the placenta
? Corpus luteum atretic gradually after 3-4
months gestation,
Changes of the circulation
Heart border,become enlargement
Heart rate,increased 10-15 beat per min at the
late pregnancy
Heart volume,increased 10% at the late
pregnancy
Cardiac output
Very important for fetal growth and development
Incrased begain 10 weeks and upto the peak
at 32 weeks
80ml/bp and keeps the level to the term
pregancy
Blood pressure changes due to pregnancy
? No obvious change in Systolic pressure
? Mild decreased in diastolic pressure
Vein pressure
? No significantly changes in Upper limb vein
pressure
? Lower limb vein pressure increased because of
the disturbance of vein reflux
Changes of blood system
Volume,increased (30-45% ) begain 6- 8 weeks
and up to the peak at 32-34 weeks
increased about 1500ml including
plasma 1000ml and red cell 500ml
Changes of blood component
Red cell,reticulocyte increased
red cell decreased 3.6× 1012(4.2× 1012)
Hb decreased 110g/L(130g/L)
WBC,neutrophilic granulocyte increased
lymphocyte mild increased
no change in orther blood cells
Coagulation
Hypercoagulability
Factor ⅱⅴⅶ ⅷ Ⅸ ⅹ increased
ESR increased significantly upto 100mm/h
Plasma protein
albumin decreased
Zhao aimin
Definition of pregnancy
Pregnancy is defined as the course of
embryo and fetal growth and
development in uterine
It begain at the fertilization and end the
delivery of the fetal and it’s attachment
Definition of fertilazation
Fertilization is defined as the course
of combination of the oocyte and
sperm
It onset 12h after ovulation usually in
ampulla of the oviduct(fallopian tube)
The Development of the
fertilizated egg
? 3 days after ovulation,the morula
(early blast)is fomulated
? 4 days after ovulation,the late blast
is fomulated
? 6-7 days after ovulation,the egg
imbeds in the uterus
The stage of egg imbed
? Apposition
? Adhesion
? Penetration
The necessary conditions
of imbed
? Disapearing of the pellucid zone
? Syntrophoblast formed from the
blast
? Synchronizing development of blast
and the endometriun
? P Secretory enough
Changes of endometrium after
the egg imbed
The
endometrium
changes into
dicedua
?Basal decidua
?Capsular
decidua
?True decidua
Attachment of the fetal
? Placenta
? Fetal membranes
? Umbilical cord
? Amniotic fluid
placenta
It’s an exchange organ between
maternal and fetal
? Amniotic membrane
? chorion frondosum
? Basal decidua
chorion frondosum
13-21 days after ovulation,villi
fomulating gradually
? Grade I viili
? Grade II Iviili
? Grade III viili
Structure of placenta
? Round
? Weight:450-650g
? Diameter:16-20cm
? Thickness:1-3cm
thick in center and thin in margin
Function of placenta
One important function of placenta is
substance exchange between maternal
and fetal
The position of exchange is VSM(vasculo-
syncytial membrane)
VSM is comprised of
? Syntrophoblastocyte
? Basal membrane of Syntrophoblastocyte
? Stroma of villi
? Basal membrane of capillary
? Endothelium of capillary
The way of substance exchange
?Simple diffusion
?Facilitated diffusion
?Active transportion
?phagocytosis
The functions of placenta
? Gas exchange
? Suply of nutrition
? Depletion of fetal product of metabolisn
? Defense function
?Hormone synthesis
?Human chorionic gonadotropin(HCG)
?Human placental lactogen(HPL)
?Pregnancy specific ?-glycoprotein(PS ?1G)
?Human chorionic thyrotropin(HCT)
?Estrogen,P,Oxytocinase,heat stable alkaline
phosphatase(HSAP)
Fetal membrane
? Chorion
? Amnion
Umbilical cord
? Length:30-70cm average:50cm
? Consist of 2 artery and 1 vein
Amniotic fluid
?Source,early from serum dialysis
late fron fetal urine
Absorse,by fetal membrane,fetal
swallowing(500ml/day)
Amniotic exchange,between maternal
and fetal 400ml/h
Volume of amniotic fluid
? 8 weeks:5-10ml
? 10 weeks:30ml
? 20 weeks:400ml
? 38 weeks:1000ml
Status of amniotic fluid
? pH:7.20
? Density:1.007-1.025
? Contained,water(98-99%)
inorganic substance
organic substance(1-2%)
The function of amniotic fluid
Protect maternal and fetal
Maternal changes during pregnancy
The maternal system may produce a
series of changes in order to adapt to the
needing of fetal growth and development
influenceed by placenta hormone and
neuro-endocrine
Changes of reproductive system
Uterus
Body,become enlargement and soft
from 7× 5 × 3cm pre-pregnancy to
35× 25 × 22cm at term
Volume of uterus cavity,
become enlargement from 5ml pre-pregnancy to
5000ml.at term
Weight,be increased from from 50g pre-
pregnancy to 1000g at term
Wall,become thickness and the thickist at mid-
period from 1 cm pre-pregnancy to 2-2.5
cm at term
Blood suply:blood flow increased significantly
upto 500- 700ml/min,increased 4-6
times and most of blood flow is
transported to the placenta(80-85%)
Isthmus,be dialated and become soft from 1cm
pre-pregnancy a portion of the uterus
after 12 gestational weeks
Cervix,be soft and coloration or stain
secrete amount of mucus avoiding the
uterus cavity suffer from infection
Changes of ovary
? Stop ovulation
? Corpus luteum formation and maintains for
10 weeks
? And the function of corpus luteum is
substituted by the placenta
? Corpus luteum atretic gradually after 3-4
months gestation,
Changes of the circulation
Heart border,become enlargement
Heart rate,increased 10-15 beat per min at the
late pregnancy
Heart volume,increased 10% at the late
pregnancy
Cardiac output
Very important for fetal growth and development
Incrased begain 10 weeks and upto the peak
at 32 weeks
80ml/bp and keeps the level to the term
pregancy
Blood pressure changes due to pregnancy
? No obvious change in Systolic pressure
? Mild decreased in diastolic pressure
Vein pressure
? No significantly changes in Upper limb vein
pressure
? Lower limb vein pressure increased because of
the disturbance of vein reflux
Changes of blood system
Volume,increased (30-45% ) begain 6- 8 weeks
and up to the peak at 32-34 weeks
increased about 1500ml including
plasma 1000ml and red cell 500ml
Changes of blood component
Red cell,reticulocyte increased
red cell decreased 3.6× 1012(4.2× 1012)
Hb decreased 110g/L(130g/L)
WBC,neutrophilic granulocyte increased
lymphocyte mild increased
no change in orther blood cells
Coagulation
Hypercoagulability
Factor ⅱⅴⅶ ⅷ Ⅸ ⅹ increased
ESR increased significantly upto 100mm/h
Plasma protein
albumin decreased
